A typical car wash installation includes a number of treatment stations typically constructed with vertical beams mounted on floor plates. To form an arch, two or more such support structures are mounted on opposite sides of a wash lane. A bridge structure is mounted between the two vertical support structures and car wash components such as rotatable brushes or air blowers may be mounted thereon. The brushes may either be top brushes with essentially horizontal axes of rotation or side brushes with essentially vertical axes of rotation. Other components such as spray bars, nozzles, mitter curtains and air blowers may also be mounted to such structures with or without horizontal cross bridges.
Many car wash installations are at least partially fabricated on site. This may require cutting beams to length as well as securing structures to one and other by welding and/or bolting operations. Hollow aluminum and lighter gauge steel beams are preferred in such situations because they are light, easy to transport and handle, and easier to cut to the desired length than, for example, steel I-beams. In the past, square or rectangular section beams have been used. While effective, structures built with square or rectangular beams exhibit relatively little aesthetic appeal. In addition, wires and hoses are usually attached to the external surfaces of such beams.